Kacheong Poon writes: > Henk Langeveld wrote: > > > I have a concern about checksum off-load - how is e2e integrity guarded? > > This may have been beaten to death already, but I just wonder how it is > > handled. > > > If an app is really concerned about e2e integrity, it should > do its own integrity checking. The TCP checksum is pretty > weak after all.
Or use a transport such as SCTP that's stronger. One of the trade-offs of checksum off-load is that you can't guard against errors that occur somewhere between the network interface device itself (where the generation/check takes place) and the transport layer. It's always been the case that there's an unprotected path from the transport layer up through the application itself. So, at least in a strict definition, we're not talking about end-to-end anyway, but rather degrees of protection. (No application just 'ends' at TCP.) If you were hoping that TCP checksums would protect against (say) DMA errors between the network device and the stack itself, that protection is disabled by off-load. The trade-off you get is not having to waste CPU time looking at every byte against the unlikelihood of such (system design) errors. -- James Carlson, KISS Network <[EMAIL PROTECTED]> Sun Microsystems / 1 Network Drive 71.232W Vox +1 781 442 2084 MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 1677 _______________________________________________ networking-discuss mailing list [email protected]
